C语言程序设计现代方法（第2版）-课后习题答案.pdf

Chapter 2

Answers to Selected Exercises

2. [was #2] (a) The program contains one directive (#include) and four

statements (three calls of printf and one return).

(b)

Parkinson's Law:

Work expands so as to fill the time

available for its completion.

3. [was #4]

volume = height * length * width;

printf("Dimensions: %dx%dx%d", length, width, height);

printf("Volume (cubic inches): %d", volume);

printf("Dimensional weight (pounds): %d", (volume + 165) / 166);

return 0;

}

4. [was #6] Here's one possible program:

#include <stdio.h>

printf("Value of i: %d", i);

printf("Value of j: %d", j);

printf("Value of k: %d", k);

printf("Value of x: %g", x);

printf("Value of y: %g", y);

Value of i: 5618848

Value of j: 0

Value of k: 6844404

Value of x: 3.98979e-34

Value of y: 9.59105e-39

Value of z: 9.59105e-39

The values printed depend on many factors, so the chance that you'll get

exactly these numbers is small.

5. [was #10] (a) is not legal because 100_bottles begins with a digit.

8. [was #12] There are 14 tokens: a, =, (, 3, *, q, -, p, *, p, ), /, 3,

{

float original_amount, amount_with_tax;

}

The amount_with_tax variable is unnecessary. If we remove it, the program

is slightly shorter:

#include <stdio.h>

printf("Enter an amount: ");

scanf("%f", &original_amount);

printf("With tax added: $%.2f\n", original_amount * 1.05f);

(a) printf("%-8.1e", x);

(b) printf("%10.6e", x);

(c) printf("%-8.3f", x);

(d) printf("%6.0f", x);

5. [was #8] The values of x, i, and y will be 12.3, 45, and .6, respectively.

Answers to Selected Programming Projects

1. [was #4; modified]

#include <stdio.h>

int main(void)

return 0;

}

3. [was #6; modified]

int prefix, group, publisher, item, check_digit;

printf("Enter ISBN: ");

scanf("%d-%d-%d-%d-%d", &prefix, &group, &publisher, &item,

&check_digit);

printf("Group identifier: %d\n", group);

printf("Publisher code: %d\n", publisher);

code: %d\nItem number: %d\nCheck digit: %d\n",

prefix, group, publisher, item, check_digit);

*/

return 0;

}

Chapter 4

Answers to Selected Exercises

2. [was #2] Not in C89. Suppose that i is 9 and j is 7. The value of (-i)/j

(b) 3 2 1

(c) 2 -1 3

(d) 0 0 0

13. [was #8] The expression ++i is equivalent to (i += 1). The value of

both expressions is i

the increment has been performed.

Answers to Selected Programming Projects

2. [was #4]

#include <stdio.h>

int main(void)

{

return 0;

}

Chapter 5

Answers to Selected Exercises

2. [was #2]

(a) 1

(b) 1

(c) 1

(d) 1

4. [was #4] (i > j) - (i < j)

2. [was #6]